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Great Barrier coral reef : Is it capable of regenerating itself?

The Guardian reports, 29th November 2017: A group of “source” reefs have been identified that could form the basis of a life support system for the Great Barrier Reef, helping repair damage by bleaching, starfish and other disturbances.

Researchers from the University of Queensland, CSIRO, Australian Institute of Marine Science and the University of Sheffield searched the Great Barrier Reef for ideal areas that could potentially produce larvae and support the recovery of other damaged reefs.

The Great Barrier Reef is the world’s largest living structure and is made up of more than 3800 individual reefs, stretching 2300km down Australia’s eastern coastline.

The study found 112 “robust source reefs” — just 3% of the entire system — which had “ideal properties to facilitate recovery” of others by spreading fertilised eggs to replenish other areas.

“Finding these 100 reefs is a little like revealing the cardiovascular system of the Great Barrier Reef,” said Prof Peter Mumby, from the University of Queensland’s school of biological sciences and ARC Centre of Excellence in Coral Reef Studies.

Researchers had strict criteria — the reefs must be consistently well connected to other reefs through the constantly shifting currents, be less likely to die in a coral bleaching event and be less susceptible to crown-of-thorn starfish outbreaks.

These reefs were more likely to still be standing in the event of bleaching incidents, for example, and were in the right location to send fertilised eggs to the reefs that need them during the annual reproduction, Mumby said.

“It gives us a bit more hope that the capacity for the barrier reef to heal itself is greater than we expected.”

There have been four significant bleaching events on the Australian reef, including one this year. The longest and worst for the Great Barrier Reef was in 2016, when bleaching caused by climate change killed almost 25% of the reef.

Scientists have only recently been able to understand how connected the reefs are by ocean currents, Mumby said.

“The Great Barrier Reef is about the size of Italy and at any given time there are patches that have been damaged and patches that are pretty good, so it has an ability to heal itself if you like.”

The researchers used ocean circulation simulations to model the connectivity of the reef larvae across the Great Barrier Reef and generated 208 networks, through which the 112 strong reefs could reach almost half of all reefs through their “amazing capacity to connect the wider system”.

“It’s not perfect,” Mumby said. “There are areas in the northern barrier reefs where there are relatively few of these reefs identified.

“It’s very clear that in order to maintain a beautiful reef into the future, we absolutely need to be much more aggressive in our response to climate change,” Mumby said. “We need coherent policies in government about what government is trying to achieve in our actions towards climate change and we need to continue to invigorate the local protections.”

Marinet observes: Whilst it is encouraging news that “robust source reefs” may survive bleaching events caused by the warming of the sea, and so be able to infuse the seeds of life into the dead areas, this is itself not the solution.

This may be nature’s solution to an extreme experience, but the repetition of these experiences is being caused by climate change — induced by mankind. Therefore if mankind is to solve this problem it is not by “management of the reefs”, but rather by management of mankind’s own activities.

This means tackling climate change.

As long as this issue continues unresolved, the grave threat to coral reefs remains — and this threat grows greater by the month and the year as the CO2 levels in the atmosphere continue to rise. So let’s be clear about where the focus needs to be if we are to talk about this problem being “solved”.

That means we must halt the continued escalation of CO2 levels in the atmosphere due, primarily, to the uncontrolled burning of fossil fuels and deforestation.